GB 2,311,812A published on Oct. 8, 1997 discloses a clutch mechanism designed for a powered sliding device and provided between a wire drum and a motor, which has a first coupled state for transmitting a closing rotation of the motor to the wire drum, a second coupled state for transmitting an opening rotation of the motor to the wire drum, and an uncoupled state of transmitting neither an opening rotation nor a closing rotation of the drum to the motor, and wherein said clutch mechanism is displaceable to the first coupled state by the closing rotation of the motor and is displaceable to the second coupled state by the opening rotation of the motor, and wherein said clutch mechanism is held in the first coupled state or in the second coupled state when the rotation of the motor is stopped by deenergizing the motor when the clutch mechanism is in the first coupled state or in the second coupled state, and wherein said clutch mechanism is returned to the uncoupled state by the opening rotation of the motor by a predetermined amount when the clutch mechanism is in the first coupled state, and said clutch mechanism is returned to the uncoupled state by the closing rotation of the motor by the predetermined amount when the clutch mechanism is in the second coupled state.
A problem to be solved of the above prior art clutch mechanism is that it has no brake mechanism or no brake state for preventing the wire drum from being rotated at an over speed. Therefore, when a powerful external force in a direction of accelerating the door is applied to the door by an intensive inclination of the vehicle body, it is impossible to prevent the door from moving at the over speed.
Furthermore, another problem to be solved of the above prior art clutch mechanism is that an emergency release mechanism of the clutch mechanism is not practical. In the clutch mechanism which is caused to be returned to the uncoupled state from the coupled state by the power of the motor, the emergency release mechanism for returning the clutch mechanism to the uncoupled state from the coupled state by the manual operation, is required when the motor is out of order. However, the emergency release mechanism of the prior art clutch mechanism requires a very complex and troublesome operation when the slide door is fully closed or the slide door is fully opened.
Furthermore, GB 2,311,812A also discloses a tension mechanism for a powered sliding device, which comprises a housing, a wire drum rotatably attached to the housing with a drum shaft, a wire cable for coupling the wire drum with the slide door, and a pair of tension rollers brought into contact with the wire cable. The wire cable has a first cable portion for pulling the door rearward or in the opening direction and a second cable portion for pulling the door forward or in the closing direction, and the tension rollers respectively come into contact with the first cable portion and the second cable portion.
The problem to be solved of the prior art tension mechanism is that there are two pieces of tension rollers which are respectively directly attached to the housing. Therefore, the tension rollers can absorb the slack of the wire cable in use, but cannot apply an initial tension to the wire cable.
Furthermore, U.S. Pat. No. 5,239,779 discloses a powered sliding device which comprises a sensor or a switch for detecting an open state of the slide door (refer to column 14, lines 14 and 15).
As the prior art switch is designed to detect the position of the door by the contact with the door, it is attached at a place completely away from the housing to which the wire drum of the powered sliding device is attached. This requires a new independent installation work of the signal cable which connects the controller of the sliding device and the switch.